[phobos] Interest in having a serializer in Phobos?

[Michel Fortin]

Le 2010-08-08 à 11:31, Andrei Alexandrescu a écrit :

> Good point. This is not a template-specific problem; if you try to deserialize a derived class and the client doesn't know of that class... well there's not a lot one can do, unless you package the code of the methods with the object.
> 
> I think it's reasonable to limit (at least for now) things to requiring that the client knows about the exact type serialized. And they need to have a layout-compatible version. Which brings us to a related problem - versioning...

My preferred way to handle versioning is to not have to handle it. I generally use key-value pairs to store the content of aggregates (structs, classes). This means I can grow the number of members over time while keeping backward compatibility. If a member is missing from the serialization I use the default value or the class/struct can handle the case with a more specialized behaviour. I can also continue serializing a no-logner necessary value to keep the aggregate backward compatible with older code.

This also makes things less fragile in regard to layout changes: you don't need to keep variables in the same order on all platforms, in all versions, etc.

So that's how I've build my serialization module. I probably should stop talking about it and finish it instead... :-)

-- 
Michel Fortin
michel.fortin at michelf.com
http://michelf.com/